The present invention concerns novel self-cross linkable acrylic resins containing hydroxyalkyl carbamate groups and coating compositions containing the same.
The reaction of propylene carbonate with primary and secondary amines to produce corresponding 2-hydroxypropyl carbamates is known in the art (Comp. rend, 1142, 1954). Similar reactions of ethylene carbonate are exemplified by the article, "The Preparation of Polymeric and Cyclic Urethans and Ureas from Ethylene Carbonate and Amines" by Elizabeth Dyer and Harvey Scott, J.A.C.S. (1956) pp. 672-675. See also the report "Polyurethane elastomers obtained without the use of diisocyanates" by L. Ya. Rappoport, G. N. Petrov, I. I. Trostyanskaya and O. P. Gavrilova in Internaional Polymer Science and Technology, 8, No. 1, 1981. The Dyer-Scott reference discloses that polyurethanes might be prepared from 2-(hydroxyethyl)-carbamate by elimination of ethylene glycol, thereby avoiding the need for using diisocyanates. The Rappoport et al paper discloses generally the reaction of cyclic carbonates with amines to form polyurethane elastomers. Thus, the prior art shows an awareness that amines react with, e.g., propylene carbonate, to yield the corresponding hydroxyalkyl carbamates. The Journal of Polymer Science, Vol. 7, 899 916 (1969), in an article entitled " New Method for Preparing Saturated and Unsaturated Aliphatic Polyurethanes" by Y. Mizake, S. Ozaki and Y. Hirata, at pages 899-915, discloses alternate routes to saturated and unsaturated polyurethanes, including polycondensation reaction of glycol bis(chloroformate) with diamine.
An article by Richard D. Cowell entitled "Thermoplastic Polyurethane Elastomers: Chemistry Properties and Processing for the 80's" in the Journal of Elastomers and Plastics, Vol. 14, (October, 1982) pages 195-203, discloses the preparation of bis(2-hydroxyethyl) carbamates by reaction of diamines with ethylene carbonate followed by a catalyzed transesterification reaction with a glycol or macroglycol.